Toyota 4Runner: Check For Intermittent Problems

Toyota 4Runner Service Manual / Brake / Brake Control / Dynamic Control Systems / Vehicle Stability Control System(for Hydraulic Brake Booster) / Check For Intermittent Problems

CHECK FOR INTERMITTENT PROBLEMS

1. DESCRIPTION

HINT:

A momentary interruption (open circuit) in the connectors and/or wire harness between the sensors and ECUs can be detected through the ECU data monitor function of the Techstream.

(a) Turn the ignition switch off.

(b) Connect the Techstream to the DLC3.

(d) Turn the Techstream on.

(e) Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.

(f) Select areas where momentary interruptions should be monitored.

HINT:

A momentary interruption (open circuit) cannot be detected for 3 seconds after the ignition switch is turned to ON (initial check).
If Error is displayed, check for continuity between the ECUs and the sensors or between ECUs.
Error remains displayed on the Techstream for 1 second after the harness signal changes from a momentary interruption (open circuit) to normal.

ABS/VSC/TRAC

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
FR Speed Open	Front speed sensor RH open circuit detection/ Error or Normal	Normal	-
FL Speed Open	Front speed sensor LH open circuit detection/ Error or Normal	Normal	-
RR Speed Open	Rear speed sensor RH open circuit detection/ Error or Normal	Normal	-
RL Speed Open	Rear speed sensor LH open circuit detection/ Error or Normal	Normal	-
EFI Communication Open	ECM communication open circuit detection/ Error or Normal	Normal	-
Yaw Rate Open	Yaw rate and acceleration sensor open circuit detection/ Error or Normal	Normal	-
Deceleration Open	Deceleration sensor open circuit detection/ Error or Normal	Normal	-
Steering Open	Steering angle sensor open circuit detection/ Error or Normal	Normal	-
Master Cylinder Open	Master cylinder pressure sensor open circuit detection/ Error or Normal	Normal	-
IG Voltage Value Decreased	IG1 voltage value decreased detection/ Error or Normal	Normal	-
IG Voltage Value Increased	IG1 voltage value increased detection/ Error or Normal	Normal	-
FR Speed Sensor Voltage Open	Front speed sensor RH voltage open circuit detection/ Error or Normal	Normal	-
FL Speed Sensor Voltage Open	Front speed sensor LH voltage open circuit detection/ Error or Normal	Normal	-
RR Speed Sensor Voltage Open	Rear speed sensor RH voltage open circuit detection/ Error or Normal	Normal	-
RL Speed Sensor Voltage Open	Rear speed sensor LH voltage open circuit detection/ Error or Normal	Normal	-
M/C Pressure Sensor Noise	Master cylinder pressure sensor noise detection/ Error or Normal	Normal	-
Yaw Rate Sensor Voltage Open	Yaw rate and acceleration sensor voltage open circuit detection/ Error or Normal	Normal	-
EFI Communication Invalid	ECM communication invalid detection/ Error or Normal	Normal	-

(g) While observing the screen, gently jiggle the connectors or wire harnesses between the ECUs and sensors or between ECUs.

OK:

Normal display appears.

HINT:

The connector and/or wire harness has a momentary interruption (open circuit) if the display changes. Repair or replace the connectors and/or wire harnesses as one of them is faulty.

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